Epoxysilanes are chemically reactive materials which are useful in various commercial applications. For example, such compounds are useful as coupling agents. In particular, 3-glycidoxypropyltrimethoxysilane is widely used as an additive in epoxy resins used in the manufacture of circuit boards. This particular compound has the formula ##STR1## and is sometimes referred to herein for brevity as "GPTMS".
Epoxysilanes are prepared by the known reaction of organosilicon compounds having an Si--H functional group and an epoxy-containing compound. For example, GPTMS is prepared by reacting allyl glycidyl ether and trimethoxysilane. Although the resulting product is chemically stable, it can over time undergo degradation resulting in the formation of various ionic by-products. These by-products include formate, acetate and glycolate ions, which are undesirable in the product In critical, high purity applications, commonly encountered in the electronics industry, these ionic impurities may render the product unusable for its intended purpose.
The degradation of epoxysilanes is a function of many variables, such as time, oxygen content and temperature. Improperly inhibited material may be acceptable for a particular application initially, but over time, the level of impurities increases rendering the material unusable. The continuous degradation of the material results in increased testing costs to determine if the silane is still acceptable or in increased off-specification production if an unacceptable epoxysilane is used.
Currently, nitrogen blankets are employed to prevent the degradation of epoxysilanes. The shortcomings of this technique include the need for an available nitrogen source and the cost of the nitrogen. Further, when only relatively small quantities of epoxysilanes are used, such as can be supplied from fifty-five gallon supply drums, replacing the nitrogen blanket after the necessary amount of epoxysilane is removed is often impractical.
Accordingly, a need exists to stabilize epoxysilanes against degradation with an inhibitor which is capable of inhibiting the degradation and which does not require special process features to be effective. It is also desirable that the inhibitor not adversely affect the properties of the product.